What Is Solid Waste?
When you throw away your trash, you are actually throwing what is formally called municipal solid waste (MSW). Solid waste refers to a wide range of waste material consisting of useless or unwanted items that the public uses daily. Such waste is often produced from residences as well as commercial, industrial, agricultural, medical, and radioactive sources.
Solid waste materials that are regulated by the US federal Environmental Protection Agency’s (EPA) Resource Conservation and Recovery Act (RCRA) are classified as solid waste. Note that only waste materials that meet the strict definitions of solid waste under RCRA are defined as such. The EPA also develops regulations that delineate which kinds of solid wastes are classified as non-hazardous and hazardous.
It is important for public agencies and private businesses that are assigned or desire to delve into solid waste management to understand these definitions. The same holds true for generators of such wastes. Such understanding is a crucial initial step in waste management programs; it helps all entities properly determine if the wastes they generate or process are non-hazardous or regulated hazardous materials.
Being home of two industrialized countries, North America produces the highest average amount of waste per capita at 4.6 pounds daily. In fact, in 2016, the continent generated over 289 million tons. However, North America has a universal waste collection at 99.7%. This means that all states, cities, and counties have some sort of solid waste management program.
Roughly 55% of the waste in North America is made of recyclable materials such as plastic, metal, glass, cardboard, and paper. The rest goes to sanitary landfills. Even then, 1/3rd of landfill wastes are recycled at some point.
No matter the content, origin, or hazard potential, solid waste should be properly managed. Otherwise, it would negatively affect the environment and threaten public health. Solid waste management should be included into a region’s environmental planning.
Objectives of Solid Waste Management
Solid waste is churned out daily in tons. These wastes must go somewhere. But without proper management of waste disposal, the accumulation of improperly discarded or processed waste will pollute our environment and pose a public health hazard.
Thus, each local government must have a sound solid waste management plan. The aim is to lessen or even eliminate adverse impacts of generated waste material on public health and the environment. Such programs should also support economic development and encourage a better quality of life for everyone in society.
Solid waste management must also be conceptualized, planned, designed, and implemented in the most efficient manner possible. This is to keep the cost of processing and disposing wastes low and prevent the buildup of waste material. After all, landfills are finite.
Solid Waste Characteristics
RCRA defines “solid waste” as any garbage or refuse material resulting from common community activities of households, commercial establishments, industrial facilities, agricultural operations, and so on. Note that this definition is not constricted to materials that are physically solid. It also includes semi-solid, liquid, or gaseous waste materials.
According to the EPA RCRA, solid waste is an item or material that is disposed by being:
- Abandoned – materials that are thrown away or incinerated.
- Inherently Waste-Like – obvious waste materials that threaten human health and environmental well being.
- Discarded Military Munitions – unused or defective ammunition products and components that are produced or used by the armed forces or the Department of Defense. Such ammunition may be abandoned, treated, or rendered unusable. Used, fired, or detonated ammunition are considered solid wastes provided they’re collected for storage, recycling, treatment, or disposal.
- Recycled In Some Ways – waste material that is recycled for use or reuse in some way (e.g., as an ingredient to a new material or process)
Materials that do not meet these criteria are not considered solid wastes. As such, they are not subject to RCRA regulations. As regulations change and as new materials are invented and introduced to the public, the waste composition changes. Solid waste can include the following:
- Biodegradable Waste - food and kitchen waste, dried leaves, grass clippings
- Recyclable Materials - plastic bottles, glass, paper, cardboard, aluminum cans, tires, aluminum foil
- Electrical and Electronic Wastes (E-wastes) - non-functioning electrical appliances, mobile phones, watches, alarm clocks, burnt fuses
- Composite Waste - tetra food packs, toys, garden furniture
- Construction and Demolition Waste - concrete slabs, bricks, stones, gravel
- Hazardous Household Waste - cleaning fluids, light bulbs, aerosol spray cans, paint products
- Toxic Wastes - fungicides, herbicides, pesticides
- Biomedical Waste - expired medicines, used bandages
The variety of solid wastes also vary from one country to another. For example, solid wastes in the US are often lighter in weight and volume than European or Japanese material. Around 40% of American-generated solid waste is composed of paper and cardboard products while food wastes comprise about 10%. The rest are a smorgasbord of wood, glass, plastic, metal, cloth, trimmings, and other items.
The characteristics of common solid wastes in each area must be carefully analyzed prior to establishing a waste management system. They must be thoroughly studied before any transfer station, landfill, incinerator plant, treatment facility, or recycling facility can be designed or constructed.
Solid Waste Collection
An important part of solid waste management is collecting them from the sources. And it doesn’t stop on collection. Wastes should then be properly transported to a transfer station, processing facility, incinerator plant, or landfill.
Proper collection is vital for protecting public health, maintaining safety, and preserving environmental quality. The task is labor-intensive and accounts around 3/4 of the total cost of solid waste management in a given area. In most cases, the local government unit assigns public employees to do the task. However, there are also private companies that do the task, whether under contract to the local government or paid by individual households, homeowner associations, business establishments, or other facilities.
Trucks that store collected solid wastes are fully enclosed and have a built-in compactor. Each truck has a capacity of 30 to 40 cubic meters of compacted trash although there are bigger trucks as well.
Another challenging task for the government is scheduling and plotting out a collection route. The route must be optimized for efficient use of labor, equipment, personnel, and fuel. Service type, distance, population density, and even climate are just some of the variables needed to analyze in planning out a route and schedule. Advanced computers and algorithms are utilized to accomplish such end.
In most cases, there are designated collection points in the city. Usually, residents and personnel in business establishments can put their garbage in large trash chutes where they are later collected. Some have designated areas on the curbside rather than chutes.
Collecting solid waste also revolves around a schedule. In large cities, collection is usually daily. In suburban or sparsely populated communities, collection is around once or twice a week. In addition, there are also scheduled collections for certain types of wastes. For example, collection of regulated hazardous wastes and burned out fluorescent lamps may be scheduled one a month.
Finally, some places have drop-off centers where people can drop off their recyclables.
Solid Waste Treatment and Disposal
Solid waste treatment often begins at the footsteps of the waste generator. Many local government units have ordinances that require generators to first segregate their wastes. In addition, generators are encouraged to reduce the production of waste materials through recycling, repurposing, or composting.
Once collected, the waste materials may first be transported to a transfer station. This is a facility where waste materials gathered by several collection vehicles are dumped and stored. From here, waste materials are transferred to larger, open-topped trucks that transport the waste to incinerator plants, recycling facilities, or landfills.
Depending on the municipality’s regulations, solid waste may need to be treated and processed before final disposal. These processes may occur at the transfer station, recovery facility, recycling plant, or incinerator. Treatments and processes may include:
- Composting – organic waste such as food waste and grass clippings can be composted; this can even be done at the source. Compost uses the natural process of decomposition using loam soil, worms, or enzymes. The resulting material is compost - which can then be used as a soil conditioner or fertilizer.
- Segregation – wastes materials may be further segregated in the end facility. Specialized machinery may be used to perform the segregation quickly and effectively. However, many facilities employ personnel to help in segregation. Recyclable materials are separated from non-recyclable ones.
- Chemical or Mechanical Treatment for Sterilization – some solid wastes may need to undergo chemical or mechanical treatments before they can be safely disposed of. For example, used fluorescent bulbs must be crushed in a vacuumed drum. The vacuum extracts the toxic mercury, which could be reused, from the bulbs. The broken glass is then either recycled as aggregate or packed for disposal.
- Incineration – waste materials can be burned in an incineration plant. These incinerators are designed with multiple incineration chambers so that even the gasses that are emitted from the burning process are oxidized. The result is a much cleaner gas released into the atmosphere. The process oxidation process also eliminates or reduces fly ash such as smoke, cinders, dust, soot, and other particulates from being ejected into the air.
- Waste-To-Energy Recovery (WTE) – the heat and steam generated from burning solid waste material can be made to run turbines in the incineration facility. These turbines then produce electricity which can be used to power the plant or feed to the nearby grid.
WTE systems are more expensive to build and maintain than normal incinerators. It also requires special equipment and trained personnel to operate the facility. But the cons outweigh the positives brought about by WTE facilities. In fact, 80% of municipal waste incinerators in the US are WTE facilities.
The leftover materials from these processes are then sent to the landfill for final disposal.
Solid Waste Regulation
In the US, the federal Environmental Protection Agency (EPA) is the government body that makes the regulations for household, commercial, and industrial solid and hazardous wastes. It does this under the Resource Conservation and Recovery Act. Aspects of EPA’s role include:
- Creating Laws & Regulations
- Compliance
- Enforcement
- Creating Guidelines
- Recycling Protocols
The Department of Transportation (DOT) regulates the transportation and shipping aspect of solid waste.
The exact guidelines are too broad to discuss given the scope of this article. You can click this link for details about EPA’s regulatory information about solid waste management.
Integrated Solid Waste Management (ISWM)
As the economy grows exponentially, more and more solid waste is produced each day. Thus, more effective, systematic, contemporary, and holistic solutions need to be considered. One of these is Integrated Solid Waste Management (ISWM). This refers to an all-inclusive waste management system defined by the EPA.
The system first involves assessment of a certain locality’s conditions, preferences, and needs. After these are identified, the EPA as well as state governments will choose, mix, and apply the best, most appropriate, and most effective solid waste management activities in accordance with those conditions, preferences, and needs.
The four main components of an ISWM program include waste source reduction, recycling, composting, waste transportation, and land filling. These activities can be done interactively or in a hierarchy.
Solid Waste Management History
During the ancient times, waste materials were carelessly thrown into streets and rivers and left to accumulate. The growing piles of waste soon became a threat to public health, causing plagues and epidemics. In 320 BC, the city of Athens created the first known law that prohibits such careless disposal. Soon, in ancient Rome, property owners were held responsible for tidying up the streets in front of their properties.
At the end of the 14th century, scavengers were tasked with carting away waste materials to dump sites outside the European city walls. It was in America during the end of the 18th century that crude municipal garbage collection began to take place, particularly in the cities of New York, Boston, and Philadelphia.
A true technological and systematic approach to solid waste management in the US was developed at the end of the 19th century. Innovations such as watertight garbage cans, compactor vehicles, garbage grinders, incinerators, and pneumatic collection systems began to flourish.
Around 1950, improper dumping and burning of solid waste began to cause environmental problems and threatened to endanger public health. As a result, sanitary landfills were developed to replace open dumping. New incinerators were designed with air pollution control devices and heat energy recovery systems.
Government agencies began to craft regulations to encourage segregation, recycling, and source waste reduction. Both federal and state governments also enacted laws to ensure the processing and disposal of solid waste is done in ways that mitigate their negative impact to public health and the environment.
Conclusion
As long as there is human activity, solid waste will be a part of us. But the good thing is that by exercising a sense of responsibility and following sensible regulations, we can definitely live a better and cleaner life even with solid waste around.
ACT Enviro is your partner in safe, compliant solid waste management. To know more about our services, contact our team today.
